Sound recording and reproducing machine.



M. CALDERON. SOUND RECORDING AND REPRODUCING MACHINE. APPLICATION FILED MAR. 10. 19:1.

1 ,290,7 1 1 Patented Jan. 7, 1919.

3 vwemtoz WW! maew m MANUEL GALDERON, OF NEW YORK, N. Y.

SOUND RECORDING AND REPRODUCING MACHINE.

Specification of Letters Patent.

Patented Jan. 7 1919.

Application filed March 10, 1917. Serial No. 153,816.

To all whom it may concern:

Be it known that I, MANUEL CALDERQN,

.a citizen of the Republic of Mexico, residing in the city, county, and State of New York, have invented an Improvement in Sound Recording and Reproducing Machines, of which the following is a specification.

The present invention relates to improvements in apparatus for recording and reproducing sound and moreparticularly to apparatus capable of use with moving picture machines, one object of this invention being to provide a sound reproducing device which will not reproduce the scraping orgrating effect commonly associated with the reproduction of sound by meansnow ordinarily used. Other more specific objects and uses of the invention will appear from the following description of one embodiment of my invention as illustrated in the drawings which accompany this specification and in which, v

Figure l is a side elevation of the recording instrument with portions of the apparatus illustrated diagrammatically.

Fig. 2 is a detail view of a modified form of electromagnet adapted to be conveniently used in connection with apparatus as disclosed in Fig. 1.

Figs. 3, 8", and 3" are enlarged details in side elevation, plan, and end elevation respectively of the manner of. securing the spring to one of the levers hereinafter described.

In making a sound record according to the present invention, the sound waves may be directed into a suitable transmitter .1 to

effect resistance changes in an electric circuit including an electromagnet 2. The flow of current through said circuit mayconvenientlybe controlled by a suitable rheo- I Stat 3.

One step in the practice and application of the present invention is to produce a sound record in which the variations in wave I moving picture film. For this purpose, a

film 4 suitably supported may be guided and driven by rollers 5 across the normal path of raysof light emanating from a source 6, said source-being adapted to supply light rays of substantially constant intensity. It

will be understood that the unexposed film is carried in .a light proof compartment of the light intercepting means as 7 cooperating to form an aperture or slit of any desired exapparatus which may also. embody 'movable tent for the purpose of admitting light rays 7 to the sensitized film. Between said slit and I the source of light, an objective. 8 is interposed, said objective being positioned so that its focus will substantially coincide with the sensitized film as the latter passes the slit and preferably concentrates the light along a line coincident withthe slit. Means may also be provided to vary the value of the light reaching film 4; in proportion to variations in the current operating through the transmitter circuit, said means including a shutter comprising cooperating light intercepting plates 9 and 10 mounted respectively on the longer arms of levers 11 and 12. v

Lever 11 may be pivotally mounted at 13, preferably on sharp steel .points and agate plates for the purpose 'of eliminating resistance by friction. A suitable adjustable weight 14 may be mounted on said lever in order to hold-the same normally in equilibrium. Similarly, lever 12 may bealso pivotally mounted at 15 and may have a balancing weight member 16. According to Fig. 1, both levers 11 and .12 may be provided with suitable means for absorbing trated includes a spring 17 having one end secured to the lever adjacent to its point:

of. pivotal support. The other end may engage an adjustable stop or detent 18. In a similar manner, lever 12 is provided with a 1 spring ,19 secured thereto and having its free end normally engaging an adjustable stop,

or detent 20. The stops 18 and 20 may be I made simultaneously adjustable by mounting them on a screw 21having portions oppositely threaded to engage the respectlve stops. I

The method of connecting springs 17 and I .19'will be best understood from Figs. 3, 3

and 3", Fig. 3 beinga side elevation, and

Fig. 3 a plan partly broken away upon an enlarged scale of the parts shown in Fig.1,-

which bear same reference characters. Fig.

,3 is an end elevation. In these figures, the

spring17 and armature 22 are attached to the coned axle 13, giving a very delicate suspension. The stop 20 moves in the slide 21 which also carries the screw 21, and the spring 17 is held .between the clip 20 and the top of the stop 20 as indicated. V

To translate the resistance variations in electrical circuit setup by the sound'waves encountering the transmitter 1 intovibrations measurable by extent of movement of the levers above described, an armature 22 is mounted on the spring 17 and a similar armature 23 on the sprm 19, said armature being positioned opposite the ends of the core of electromagnet 2 in such relation that variations in the resistance in the circuit, magnetically exciting said core, will attract said armatures in like proportion. Thus, the levers 11 and 12 will be deflected from their normal position of equilibrium to'an extent proportionate to the variations in resistance in the circuit and therefore to an extent proportionate to the variations in wave. length of the sound waves encountering the transmitter 1, but on a magnified scale.

These deflections of the levers 11 and 12' may be utilized to vary the amount of light passing from the source 6 through objective 8 to the film 4: at the focus of objective 8. To this end, the light intercepting plates 9 and 10 may be provided with suitable openings arranged to ermit the passage of vary ing amounts of llght from source 6 depending on the extent towhich relative movement of the plates increases or diminishes the shutter aperture thus formed. It will be observed that the apertures in the shutters 9 and 10 are located in advance of the lens orobjective 8 and not at its focus. The

variation of theopening caused by the vi-' bration of the levers under the changes of 1 current in the electro-magnet 2 thus causes changes in the parallel beam of light passing to the lens; but these changes are not, as when the-shutter is located at the focus, al-

ternately a brilliant illumination or total when the film is used for re roduction, as is intended. It Wlll be seen omFigL 1 that the aperture shutters 9 and10 constitute what I have called a combining shutter, inasmuch as both of the shutters move under the influence of the magnet 2 and the overlapping of their apertures determines the extent of the-opening of the shutter asa whole.

As shown in Fig. 1, the shutters are in what I may call a normal position and-it will be observed that they may be displaced in either direction therefrom, thus causing changes in the extent ofillumination passing to the lens 8. A'normal opening will thus produce a normal tintin of the film, while, when the aperture is increased, the darkenin is also increased and, when it is diminis ed,

the darkening is also diminished in exact conformity to the character and intensity of the sounds received by the transmitter 1.

In operation, variations in wave length of sound waves received in transmitter 1 are translated'into resistance variations therein, and cause current varlations 1n electromagnet 2, said current variations in turn being translated into relative movement between the light intercepting plates 9 and 10, thus varying the amount of light permitted to v pass through the apertures therein. This variation in the amount of light passing said apertures is recorded on film- 4 as the latter is moved past the slit in the member 7, said movement being imparted by any suitagle film actuating means, not i llus-. trate In the formation of a record of the character contemplated, it may be desirable to check u or rove the same while it is being made. whereby the variations in light va ue, coming through the film 4 may cause proportionor t is purpose, means are rovidedate resistance variations in a circuit 2 1 which may include an ordinary telephone receiver 25. In thiscircuit, the resistance variations may conveniently be efi'ected by means of a selenium cell 26 arranged in suitable position for intercepting light rays passing through the film 4. Accord ng to a well known property of selenium, its resistance is decreased in direct proportion to the'amount of light admitted to it. The selenium cell will preferably be carried in a light toward the source of light and in such a -mannerthat the resistance in said selenium may vary in proportion to-the. amount of. light which it intercepts in the manner indicated.

Fig. 2 illustrates a modification which is intended to be used for recording sounds of relatively small intensity. In this case, the electromagnetic element may include oppositely wound coils 27 and 28 in the sound transmitting circuit. The variations in current in said coils, caused by the changes in resistance in the transmitter 1, are made to I proof inclosure with a ortion of the selemum exposed actuate the levers 11 and 12 through the instrumentality of closed circ'uited coils 29 and.30 mounted on said levers respectively and penetrating part way into the coils 27 and 28. Where this construction is used, the stops or detents 18 and 20 may be moved out of engagement with the free ends of springs 17 and 19 respectively so that the levers will be entirely free to be actuated.

'By such a construction no dependence is placed .upon the springs and all movements are electro-magnetically controlled including the braking or damping effect, which is a function of the coils 29 and 30. The action of the device is therefore much smoother and it will respond more readily to fainter sounds and smaller variations thereof. Obviously, other electrical means may be substituted in place of the means hereinabove described for the purpose of controlling deflection of the said levers.

From the foregoing description and statement of the mode ofoperation of the device illustrated in Figs. 1 and 2, it will be understood that a photographic record of the variations in wave length of sounds encountering transmitter 1 will be formed on film 4. This film may then bedeveloped and fixed in the regular Well known manner.

I claim as my" invention:

1. In apparatus for producing a photo- I graphic record of sound vibrations, the combination of means for supporting a sensitized film, a source of current, a shutter, a transmitter, an electromagnet in circuit with said transmitter, and a pair of levers each adapted to carry a light intercepting portion of the shutter at one end and having an armature at the other end, said levers being pivotally mounted and normally with their respective arms in equilibrium, and said armature cofiperating with the electromagnet to efiect oscillatory movement of the levers.

2. In an apparatus for producing a photographic record of sound vibrations, the combination of means for supporting andv moving a film, a source of light, an objective through the focus of which the filmpasses, a pair of levers having long and short arms, aperturedv shutters carried on the long arms of the levers, an 'electro-mag- .net, armatures operating the short arms of ingly 'in a desired normal relation,

the'l'evers and actuated by the magnet, the shutters located between the source of light and the objective so that their movement controls the amount of light reaching the latter; a transmitter, a current-source, and

a circuit including the transmitter, the cur rent-source and the electro-magnet.

3. In apparatus for producing a photo- Y graphic record of sound vibrations, the combination of means for supporting a sensitized film, pivotally mounted levers having cooperating apertured shutter members,

electromagnetic means for actuating said levers, and means interposed between said levers and said electromagnetic means to retain said levers yieldingly in a desired normal relation. i

4. In apparatus for producing a photographic record ,of sound vibrations, the combination of means for supporting a sensitized film, pivotally mounted levers having cooperating apertured shutter members,

electromagnetic means for actuating said levers, means for retaining said levers yield:

an means for adjusting said lever retaining means.

-5. In apparatus for producmg a photographic record of sound vibrations, the combination of means for supporting a sensitized film, pivotally mounted levers having cooperating apertured shutter members, electromagnetic means for actuating said levers, an adjustable detent member adjacent to an arm of each lever, and a spring secured to each said arm and adapted to cooperate with said detent members to retain the levers yieldingly in a'desired normal relation.

In testimony whereof, I have signed my name to this specification this 9th day of March, 1917.

MANUEL CALDERON. 

